ALSA: hda/realtek - Move some alc236 pintbls to fallback table
[sfrench/cifs-2.6.git] / include / crypto / ctr.h
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * CTR: Counter mode
4  *
5  * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
6  */
7
8 #ifndef _CRYPTO_CTR_H
9 #define _CRYPTO_CTR_H
10
11 #include <crypto/algapi.h>
12 #include <crypto/internal/skcipher.h>
13 #include <linux/string.h>
14 #include <linux/types.h>
15
16 #define CTR_RFC3686_NONCE_SIZE 4
17 #define CTR_RFC3686_IV_SIZE 8
18 #define CTR_RFC3686_BLOCK_SIZE 16
19
20 static inline int crypto_ctr_encrypt_walk(struct skcipher_request *req,
21                                           void (*fn)(struct crypto_skcipher *,
22                                                      const u8 *, u8 *))
23 {
24         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
25         int blocksize = crypto_skcipher_chunksize(tfm);
26         u8 buf[MAX_CIPHER_BLOCKSIZE];
27         struct skcipher_walk walk;
28         int err;
29
30         /* avoid integer division due to variable blocksize parameter */
31         if (WARN_ON_ONCE(!is_power_of_2(blocksize)))
32                 return -EINVAL;
33
34         err = skcipher_walk_virt(&walk, req, false);
35
36         while (walk.nbytes > 0) {
37                 u8 *dst = walk.dst.virt.addr;
38                 u8 *src = walk.src.virt.addr;
39                 int nbytes = walk.nbytes;
40                 int tail = 0;
41
42                 if (nbytes < walk.total) {
43                         tail = walk.nbytes & (blocksize - 1);
44                         nbytes -= tail;
45                 }
46
47                 do {
48                         int bsize = min(nbytes, blocksize);
49
50                         fn(tfm, walk.iv, buf);
51
52                         crypto_xor_cpy(dst, src, buf, bsize);
53                         crypto_inc(walk.iv, blocksize);
54
55                         dst += bsize;
56                         src += bsize;
57                         nbytes -= bsize;
58                 } while (nbytes > 0);
59
60                 err = skcipher_walk_done(&walk, tail);
61         }
62         return err;
63 }
64
65 #endif  /* _CRYPTO_CTR_H */